Clinical:Hypoglycemia

Hypoglycemia may be defined as a clinical syndrome in which low serum glucose levels lead to symptoms of neuroglycopenia (such as altered senses and seizures) and sympathoadrenal activation. Glucose concentrations of 60 mg/dL or below may cause autonomic symptoms. Those below 50 mg/dL may cause impaired brain function.^[1]

Causes

Hypoglycemia typically occurs among individuals with diabetes, due to an imbalance of diabetic therapy, diet, and physical activity. It is not uncommon for physicians to overlook hypoglycemia that occurs in someone who does not have diabetes, in whom it may have life-threatening consequences (such as impairment while driving). Episodes of hypoglycemia may be warning signs of non-insulin related endocrine abnormalities such as pituitary insufficiency. Hypoglycemia may also arise following a drug error. Contrary to popular belief, insulinoma is only rarely a cause of hypoglycemia among individuals who do not have diabetes.

Diagnosis

Hypoglucemia manifests with signs of sympathoadrenal activation and neuroglycopenia, including sweating, tachycardia, tachypnea, anxiety, tremulousness, and nausea, altered vision, fatigue and confusion, dizziness, headache, and potentially seizures, coma, or death. The symptom presentation varies from patient to patient, but tends to be consistent between episodes in the same person.

A focused laboratory workup is imperative in individuals not known to have diabetes or in those with diabetes who are not responding to appropriate measures to remedy their hypoglycemia. The laboratory workiup should include a plasma or serum glucose level and serum insulin and C-peptide levels. If the suspicion of a hypoglycemic disorder is sufficiently high and symptomatic episodes infrequent, a supervised 72-hour fast in consultation with an endocrinologist may be warranted, to confirm hypoglycemia and determine a specific cause. At the end of the fast, plasma levels of glucose, insulin, C peptide, proinsulin, β-hydroxybutyrate, and sulfonylurea as well as measures of glucose after the injection of glucagon should elucidate the endocrinological abnormalities underlying the hypoglycemia.

Treatment

Among individuals with diabetes, hypoglycemia is treated by adjusting diet and anti-diabetic medications. In other situations, the treatment of hypoglycemia depends upon the treatment of the underlying cause of the condition.

References

1. ↑ Sharma T, Katz CM, and Rutecki GW. Unexplained Hypoglycemia: A Focused Approach to Finding the Cause. Consultant 48:9 (2008)